//-- convert UTM to Lat Lon-------------
//-- code for convert UTM to Lat Lon---------
var pi = 3.14159265358979;
var tarlat,tarlon;
var sm_a = 6378137.0;
var sm_b = 6356752.314;
var sm_EccSquared = 6.69437999013e-03;
var UTMScaleFactor = 0.9996;
//-- end code for convert UTM to Lat Lon------
/* Ellipsoid model constants (actual values here are for WGS84) */
   /* var sm_a = 6378137.0;
    var sm_b = 6356752.314;
    var sm_EccSquared = 6.69437999013e-03;
    var UTMScaleFactor = 0.9996;*/
    /*
    * DegToRad
    *
    * Converts degrees to radians.
    *
    */
    function DegToRad (deg)
    {
        return (deg / 180.0 * pi)
    }
    /*
    * RadToDeg
    *
    * Converts radians to degrees.
    *
    */
    function RadToDeg (rad)
    {
        return (rad / pi * 180.0)
    }

    /*
    * ArcLengthOfMeridian
    *
    * Computes the ellipsoidal distance from the equator to a point at a
    * given latitude.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    * GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *     phi - Latitude of the point, in radians.
    *
    * Globals:
    *     sm_a - Ellipsoid model major axis.
    *     sm_b - Ellipsoid model minor axis.
    *
    * Returns:
    *     The ellipsoidal distance of the point from the equator, in meters.
    *
    */
    function ArcLengthOfMeridian (phi)
    {
        var alpha, beta, gamma, delta, epsilon, n;
        var result;

        /* Precalculate n */
        n = (sm_a - sm_b) / (sm_a + sm_b);

        /* Precalculate alpha */
        alpha = ((sm_a + sm_b) / 2.0)
           * (1.0 + (Math.pow (n, 2.0) / 4.0) + (Math.pow (n, 4.0) / 64.0));

        /* Precalculate beta */
        beta = (-3.0 * n / 2.0) + (9.0 * Math.pow (n, 3.0) / 16.0)
           + (-3.0 * Math.pow (n, 5.0) / 32.0);

        /* Precalculate gamma */
        gamma = (15.0 * Math.pow (n, 2.0) / 16.0)
            + (-15.0 * Math.pow (n, 4.0) / 32.0);
    
        /* Precalculate delta */
        delta = (-35.0 * Math.pow (n, 3.0) / 48.0)
            + (105.0 * Math.pow (n, 5.0) / 256.0);
    
        /* Precalculate epsilon */
        epsilon = (315.0 * Math.pow (n, 4.0) / 512.0);
    
    /* Now calculate the sum of the series and return */
    result = alpha
        * (phi + (beta * Math.sin (2.0 * phi))
            + (gamma * Math.sin (4.0 * phi))
            + (delta * Math.sin (6.0 * phi))
            + (epsilon * Math.sin (8.0 * phi)));

    return result;
    }



    /*
    * UTMCentralMeridian
    *
    * Determines the central meridian for the given UTM zone.
    *
    * Inputs:
    *     zone - An integer value designating the UTM zone, range [1,60].
    *
    * Returns:
    *   The central meridian for the given UTM zone, in radians, or zero
    *   if the UTM zone parameter is outside the range [1,60].
    *   Range of the central meridian is the radian equivalent of [-177,+177].
    *
    */
    function UTMCentralMeridian (zone)
    {
        var cmeridian;

        cmeridian = DegToRad (-183.0 + (zone * 6.0));
    
        return cmeridian;
    }

    /*
    * FootpointLatitude
    *
    * Computes the footpoint latitude for use in converting transverse
    * Mercator coordinates to ellipsoidal coordinates.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    *   GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *   y - The UTM northing coordinate, in meters.
    *
    * Returns:
    *   The footpoint latitude, in radians.
    *
    */
    function FootpointLatitude (y)
    {
        var y_, alpha_, beta_, gamma_, delta_, epsilon_, n;
        var result;
        
        /* Precalculate n (Eq. 10.18) */
        n = (sm_a - sm_b) / (sm_a + sm_b);
        	
        /* Precalculate alpha_ (Eq. 10.22) */
        /* (Same as alpha in Eq. 10.17) */
        alpha_ = ((sm_a + sm_b) / 2.0)
            * (1 + (Math.pow (n, 2.0) / 4) + (Math.pow (n, 4.0) / 64));
        
        /* Precalculate y_ (Eq. 10.23) */
        y_ = y / alpha_;
        
        /* Precalculate beta_ (Eq. 10.22) */
        beta_ = (3.0 * n / 2.0) + (-27.0 * Math.pow (n, 3.0) / 32.0)
            + (269.0 * Math.pow (n, 5.0) / 512.0);
        
        /* Precalculate gamma_ (Eq. 10.22) */
        gamma_ = (21.0 * Math.pow (n, 2.0) / 16.0)
            + (-55.0 * Math.pow (n, 4.0) / 32.0);
        	
        /* Precalculate delta_ (Eq. 10.22) */
        delta_ = (151.0 * Math.pow (n, 3.0) / 96.0)
            + (-417.0 * Math.pow (n, 5.0) / 128.0);
        	
        /* Precalculate epsilon_ (Eq. 10.22) */
        epsilon_ = (1097.0 * Math.pow (n, 4.0) / 512.0);
        	
        /* Now calculate the sum of the series (Eq. 10.21) */
        result = y_ + (beta_ * Math.sin (2.0 * y_))
            + (gamma_ * Math.sin (4.0 * y_))
            + (delta_ * Math.sin (6.0 * y_))
            + (epsilon_ * Math.sin (8.0 * y_));
        
        return result;
    }


    
    /*
    * MapXYToLatLon
    *
    * Converts x and y coordinates in the Transverse Mercator projection to
    * a latitude/longitude pair.  Note that Transverse Mercator is not
    * the same as UTM; a scale factor is required to convert between them.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    *   GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *   x - The easting of the point, in meters.
    *   y - The northing of the point, in meters.
    *   lambda0 - Longitude of the central meridian to be used, in radians.
    *
    * Outputs:
    *   philambda - A 2-element containing the latitude and longitude
    *               in radians.
    *
    * Returns:
    *   The function does not return a value.
    *
    * Remarks:
    *   The local variables Nf, nuf2, tf, and tf2 serve the same purpose as
    *   N, nu2, t, and t2 in MapLatLonToXY, but they are computed with respect
    *   to the footpoint latitude phif.
    *
    *   x1frac, x2frac, x2poly, x3poly, etc. are to enhance readability and
    *   to optimize computations.
    *
    */
    function MapXYToLatLon (x, y, lambda0, philambda)
    {
        var phif, Nf, Nfpow, nuf2, ep2, tf, tf2, tf4, cf;
        var x1frac, x2frac, x3frac, x4frac, x5frac, x6frac, x7frac, x8frac;
        var x2poly, x3poly, x4poly, x5poly, x6poly, x7poly, x8poly;
    	
        /* Get the value of phif, the footpoint latitude. */
        phif = FootpointLatitude (y);
        	
        /* Precalculate ep2 */
        ep2 = (Math.pow (sm_a, 2.0) - Math.pow (sm_b, 2.0))
              / Math.pow (sm_b, 2.0);
        	
        /* Precalculate cos (phif) */
        cf = Math.cos (phif);
        	
        /* Precalculate nuf2 */
        nuf2 = ep2 * Math.pow (cf, 2.0);
        	
        /* Precalculate Nf and initialize Nfpow */
        Nf = Math.pow (sm_a, 2.0) / (sm_b * Math.sqrt (1 + nuf2));
        Nfpow = Nf;
        	
        /* Precalculate tf */
        tf = Math.tan (phif);
        tf2 = tf * tf;
        tf4 = tf2 * tf2;
        
        /* Precalculate fractional coefficients for x**n in the equations
           below to simplify the expressions for latitude and longitude. */
        x1frac = 1.0 / (Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**2) */
        x2frac = tf / (2.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**3) */
        x3frac = 1.0 / (6.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**4) */
        x4frac = tf / (24.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**5) */
        x5frac = 1.0 / (120.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**6) */
        x6frac = tf / (720.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**7) */
        x7frac = 1.0 / (5040.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**8) */
        x8frac = tf / (40320.0 * Nfpow);
        
        /* Precalculate polynomial coefficients for x**n.
           -- x**1 does not have a polynomial coefficient. */
        x2poly = -1.0 - nuf2;
        
        x3poly = -1.0 - 2 * tf2 - nuf2;
        
        x4poly = 5.0 + 3.0 * tf2 + 6.0 * nuf2 - 6.0 * tf2 * nuf2
        	- 3.0 * (nuf2 *nuf2) - 9.0 * tf2 * (nuf2 * nuf2);
        
        x5poly = 5.0 + 28.0 * tf2 + 24.0 * tf4 + 6.0 * nuf2 + 8.0 * tf2 * nuf2;
        
        x6poly = -61.0 - 90.0 * tf2 - 45.0 * tf4 - 107.0 * nuf2
        	+ 162.0 * tf2 * nuf2;
        
        x7poly = -61.0 - 662.0 * tf2 - 1320.0 * tf4 - 720.0 * (tf4 * tf2);
        
        x8poly = 1385.0 + 3633.0 * tf2 + 4095.0 * tf4 + 1575 * (tf4 * tf2);
        	
        /* Calculate latitude */
        philambda[0] = phif + x2frac * x2poly * (x * x)
        	+ x4frac * x4poly * Math.pow (x, 4.0)
        	+ x6frac * x6poly * Math.pow (x, 6.0)
        	+ x8frac * x8poly * Math.pow (x, 8.0);
        	
        /* Calculate longitude */
        philambda[1] = lambda0 + x1frac * x
        	+ x3frac * x3poly * Math.pow (x, 3.0)
        	+ x5frac * x5poly * Math.pow (x, 5.0)
        	+ x7frac * x7poly * Math.pow (x, 7.0);
        	
        return;
    }
   
    /*
    * UTMXYToLatLon
    *
    * Converts x and y coordinates in the Universal Transverse Mercator
    * projection to a latitude/longitude pair.
    *
    * Inputs:
    *	x - The easting of the point, in meters.
    *	y - The northing of the point, in meters.
    *	zone - The UTM zone in which the point lies.
    *	southhemi - True if the point is in the southern hemisphere;
    *               false otherwise.
    *
    * Outputs:
    *	latlon - A 2-element array containing the latitude and
    *            longitude of the point, in radians.
    *
    * Returns:
    *	The function does not return a value.
    *
    */
    function UTMXYToLatLon (x, y, zone, southhemi, latlon)
    {
        var cmeridian;
        	
        x -= 500000.0;
        x /= UTMScaleFactor;
        	
        /* If in southern hemisphere, adjust y accordingly. */
        if (southhemi)
        y -= 10000000.0;
        		
        y /= UTMScaleFactor;
        
        cmeridian = UTMCentralMeridian (zone);
        MapXYToLatLon (x, y, cmeridian, latlon);
        	
        return;
    }
    


    /*
    * btnToGeographic_OnClick
    *
    * Called when the btnToGeographic button is clicked.
    *
    */
	//function btnToGeographic_OnClick ()
    function btnToGeographic_OnClick(x1,y1,zone1,southhemi1)
    {                                  
        latlon = new Array(2);
        var x, y, zone, southhemi;
        x = parseFloat (x1);
        y = parseFloat (y1);
        zone = parseFloat (zone1);
		southhemi = false;
        UTMXYToLatLon (x, y, zone, southhemi, latlon);
        tarlat = RadToDeg(latlon[0]);
		tarlon = RadToDeg(latlon[1]);
        return true;
    }

 function DegToRad (deg)
    {
        return (deg / 180.0 * pi)
    }
    /*
    * RadToDeg
    *
    * Converts radians to degrees.
    *
    */
    function RadToDeg (rad)
    {
        return (rad / pi * 180.0)
    }

    /*
    * ArcLengthOfMeridian
    *
    * Computes the ellipsoidal distance from the equator to a point at a
    * given latitude.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    * GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *     phi - Latitude of the point, in radians.
    *
    * Globals:
    *     sm_a - Ellipsoid model major axis.
    *     sm_b - Ellipsoid model minor axis.
    *
    * Returns:
    *     The ellipsoidal distance of the point from the equator, in meters.
    *
    */
    function ArcLengthOfMeridian (phi)
    {
        var alpha, beta, gamma, delta, epsilon, n;
        var result;

        /* Precalculate n */
        n = (sm_a - sm_b) / (sm_a + sm_b);

        /* Precalculate alpha */
        alpha = ((sm_a + sm_b) / 2.0)
           * (1.0 + (Math.pow (n, 2.0) / 4.0) + (Math.pow (n, 4.0) / 64.0));

        /* Precalculate beta */
        beta = (-3.0 * n / 2.0) + (9.0 * Math.pow (n, 3.0) / 16.0)
           + (-3.0 * Math.pow (n, 5.0) / 32.0);

        /* Precalculate gamma */
        gamma = (15.0 * Math.pow (n, 2.0) / 16.0)
            + (-15.0 * Math.pow (n, 4.0) / 32.0);
    
        /* Precalculate delta */
        delta = (-35.0 * Math.pow (n, 3.0) / 48.0)
            + (105.0 * Math.pow (n, 5.0) / 256.0);
    
        /* Precalculate epsilon */
        epsilon = (315.0 * Math.pow (n, 4.0) / 512.0);
    
    /* Now calculate the sum of the series and return */
    result = alpha
        * (phi + (beta * Math.sin (2.0 * phi))
            + (gamma * Math.sin (4.0 * phi))
            + (delta * Math.sin (6.0 * phi))
            + (epsilon * Math.sin (8.0 * phi)));

    return result;
    }



    /*
    * UTMCentralMeridian
    *
    * Determines the central meridian for the given UTM zone.
    *
    * Inputs:
    *     zone - An integer value designating the UTM zone, range [1,60].
    *
    * Returns:
    *   The central meridian for the given UTM zone, in radians, or zero
    *   if the UTM zone parameter is outside the range [1,60].
    *   Range of the central meridian is the radian equivalent of [-177,+177].
    *
    */
    function UTMCentralMeridian (zone)
    {
        var cmeridian;

        cmeridian = DegToRad (-183.0 + (zone * 6.0));
    
        return cmeridian;
    }

    /*
    * FootpointLatitude
    *
    * Computes the footpoint latitude for use in converting transverse
    * Mercator coordinates to ellipsoidal coordinates.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    *   GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *   y - The UTM northing coordinate, in meters.
    *
    * Returns:
    *   The footpoint latitude, in radians.
    *
    */
    function FootpointLatitude (y)
    {
        var y_, alpha_, beta_, gamma_, delta_, epsilon_, n;
        var result;
        
        /* Precalculate n (Eq. 10.18) */
        n = (sm_a - sm_b) / (sm_a + sm_b);
        	
        /* Precalculate alpha_ (Eq. 10.22) */
        /* (Same as alpha in Eq. 10.17) */
        alpha_ = ((sm_a + sm_b) / 2.0)
            * (1 + (Math.pow (n, 2.0) / 4) + (Math.pow (n, 4.0) / 64));
        
        /* Precalculate y_ (Eq. 10.23) */
        y_ = y / alpha_;
        
        /* Precalculate beta_ (Eq. 10.22) */
        beta_ = (3.0 * n / 2.0) + (-27.0 * Math.pow (n, 3.0) / 32.0)
            + (269.0 * Math.pow (n, 5.0) / 512.0);
        
        /* Precalculate gamma_ (Eq. 10.22) */
        gamma_ = (21.0 * Math.pow (n, 2.0) / 16.0)
            + (-55.0 * Math.pow (n, 4.0) / 32.0);
        	
        /* Precalculate delta_ (Eq. 10.22) */
        delta_ = (151.0 * Math.pow (n, 3.0) / 96.0)
            + (-417.0 * Math.pow (n, 5.0) / 128.0);
        	
        /* Precalculate epsilon_ (Eq. 10.22) */
        epsilon_ = (1097.0 * Math.pow (n, 4.0) / 512.0);
        	
        /* Now calculate the sum of the series (Eq. 10.21) */
        result = y_ + (beta_ * Math.sin (2.0 * y_))
            + (gamma_ * Math.sin (4.0 * y_))
            + (delta_ * Math.sin (6.0 * y_))
            + (epsilon_ * Math.sin (8.0 * y_));
        
        return result;
    }


    
    /*
    * MapXYToLatLon
    *
    * Converts x and y coordinates in the Transverse Mercator projection to
    * a latitude/longitude pair.  Note that Transverse Mercator is not
    * the same as UTM; a scale factor is required to convert between them.
    *
    * Reference: Hoffmann-Wellenhof, B., Lichtenegger, H., and Collins, J.,
    *   GPS: Theory and Practice, 3rd ed.  New York: Springer-Verlag Wien, 1994.
    *
    * Inputs:
    *   x - The easting of the point, in meters.
    *   y - The northing of the point, in meters.
    *   lambda0 - Longitude of the central meridian to be used, in radians.
    *
    * Outputs:
    *   philambda - A 2-element containing the latitude and longitude
    *               in radians.
    *
    * Returns:
    *   The function does not return a value.
    *
    * Remarks:
    *   The local variables Nf, nuf2, tf, and tf2 serve the same purpose as
    *   N, nu2, t, and t2 in MapLatLonToXY, but they are computed with respect
    *   to the footpoint latitude phif.
    *
    *   x1frac, x2frac, x2poly, x3poly, etc. are to enhance readability and
    *   to optimize computations.
    *
    */
    function MapXYToLatLon (x, y, lambda0, philambda)
    {
        var phif, Nf, Nfpow, nuf2, ep2, tf, tf2, tf4, cf;
        var x1frac, x2frac, x3frac, x4frac, x5frac, x6frac, x7frac, x8frac;
        var x2poly, x3poly, x4poly, x5poly, x6poly, x7poly, x8poly;
    	
        /* Get the value of phif, the footpoint latitude. */
        phif = FootpointLatitude (y);
        	
        /* Precalculate ep2 */
        ep2 = (Math.pow (sm_a, 2.0) - Math.pow (sm_b, 2.0))
              / Math.pow (sm_b, 2.0);
        	
        /* Precalculate cos (phif) */
        cf = Math.cos (phif);
        	
        /* Precalculate nuf2 */
        nuf2 = ep2 * Math.pow (cf, 2.0);
        	
        /* Precalculate Nf and initialize Nfpow */
        Nf = Math.pow (sm_a, 2.0) / (sm_b * Math.sqrt (1 + nuf2));
        Nfpow = Nf;
        	
        /* Precalculate tf */
        tf = Math.tan (phif);
        tf2 = tf * tf;
        tf4 = tf2 * tf2;
        
        /* Precalculate fractional coefficients for x**n in the equations
           below to simplify the expressions for latitude and longitude. */
        x1frac = 1.0 / (Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**2) */
        x2frac = tf / (2.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**3) */
        x3frac = 1.0 / (6.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**4) */
        x4frac = tf / (24.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**5) */
        x5frac = 1.0 / (120.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**6) */
        x6frac = tf / (720.0 * Nfpow);
        
        Nfpow *= Nf;   /* now equals Nf**7) */
        x7frac = 1.0 / (5040.0 * Nfpow * cf);
        
        Nfpow *= Nf;   /* now equals Nf**8) */
        x8frac = tf / (40320.0 * Nfpow);
        
        /* Precalculate polynomial coefficients for x**n.
           -- x**1 does not have a polynomial coefficient. */
        x2poly = -1.0 - nuf2;
        
        x3poly = -1.0 - 2 * tf2 - nuf2;
        
        x4poly = 5.0 + 3.0 * tf2 + 6.0 * nuf2 - 6.0 * tf2 * nuf2
        	- 3.0 * (nuf2 *nuf2) - 9.0 * tf2 * (nuf2 * nuf2);
        
        x5poly = 5.0 + 28.0 * tf2 + 24.0 * tf4 + 6.0 * nuf2 + 8.0 * tf2 * nuf2;
        
        x6poly = -61.0 - 90.0 * tf2 - 45.0 * tf4 - 107.0 * nuf2
        	+ 162.0 * tf2 * nuf2;
        
        x7poly = -61.0 - 662.0 * tf2 - 1320.0 * tf4 - 720.0 * (tf4 * tf2);
        
        x8poly = 1385.0 + 3633.0 * tf2 + 4095.0 * tf4 + 1575 * (tf4 * tf2);
        	
        /* Calculate latitude */
        philambda[0] = phif + x2frac * x2poly * (x * x)
        	+ x4frac * x4poly * Math.pow (x, 4.0)
        	+ x6frac * x6poly * Math.pow (x, 6.0)
        	+ x8frac * x8poly * Math.pow (x, 8.0);
        	
        /* Calculate longitude */
        philambda[1] = lambda0 + x1frac * x
        	+ x3frac * x3poly * Math.pow (x, 3.0)
        	+ x5frac * x5poly * Math.pow (x, 5.0)
        	+ x7frac * x7poly * Math.pow (x, 7.0);
        	
        return;
    }
   
    /*
    * UTMXYToLatLon
    *
    * Converts x and y coordinates in the Universal Transverse Mercator
    * projection to a latitude/longitude pair.
    *
    * Inputs:
    *	x - The easting of the point, in meters.
    *	y - The northing of the point, in meters.
    *	zone - The UTM zone in which the point lies.
    *	southhemi - True if the point is in the southern hemisphere;
    *               false otherwise.
    *
    * Outputs:
    *	latlon - A 2-element array containing the latitude and
    *            longitude of the point, in radians.
    *
    * Returns:
    *	The function does not return a value.
    *
    */
    function UTMXYToLatLon (x, y, zone, southhemi, latlon)
    {
        var cmeridian;
        	
        x -= 500000.0;
        x /= UTMScaleFactor;
        	
        /* If in southern hemisphere, adjust y accordingly. */
        if (southhemi)
        y -= 10000000.0;
        		
        y /= UTMScaleFactor;
        
        cmeridian = UTMCentralMeridian (zone);
        MapXYToLatLon (x, y, cmeridian, latlon);
        	
        return;
    }
    


    /*
    * btnToGeographic_OnClick
    *
    * Called when the btnToGeographic button is clicked.
    *
    */
	//function btnToGeographic_OnClick ()
    function btnToGeographic_OnClick(x1,y1,zone1,southhemi1)
    {                                  
        latlon = new Array(2);
        var x, y, zone, southhemi;
        x = parseFloat (x1);
        y = parseFloat (y1);
        zone = parseFloat (zone1);
		southhemi = false;
        UTMXYToLatLon (x, y, zone, southhemi, latlon);
        tarlat = RadToDeg(latlon[0]);
		tarlon = RadToDeg(latlon[1]);
        return true;
    }

    //    -->
//-- end convert UTM to Lat Lon--------------------------------------------------------------------------->